Modulation of fatty acid-binding capacity of heart fatty acid-binding protein by oxygen-derived free radicals.

In this study, we examined the effects of exposure of heart fatty acid-binding protein (h-FABP) to chemically generated O2- or OH. with respect to its oleate binding and to its electrophoretic properties. Purified rat h-FABP at 40 microM scavenged as much as 30% O2- and 85% OH.. On the other hand, when 2 nmol (4 microM) FABP were exposed to free radicals, the maximum oleate binding capacity as measured by Scatchard analysis was reduced only by 14% and 27% for O2- and OH., respectively. The electrophoretic pattern of free radical-exposed FABP was not markedly different when examined either by the non-denaturing or by denaturing PAGE, suggesting the absence of any degradation or aggregation of FABP by O2- or OH.. It is hypothesized that O2- or OH. in physiological concentration may not alter the function of FABP markedly in the ischemic-reperfused myocardium.